The effect of pressure on electrical rock typing, formation resistivity factor, and cementation factor

Kolah-kaj, Parvin; Kord, Shahin; Soleymanzadeh, Aboozar

doi:10.1016/j.petrol.2021.108757

Cited by 13 publications

(4 citation statements)

References 32 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It could be linked to the closure of the micro/nano pore space which increases the resistivity. To investigate the effect of pressure on rock's resistivity, Kolah-kaj et al [43] studied 39 limestone samples under seven different effective pressures and obtained similar conclusions. They believed that the tortuosity factor of the samples increased with effective pressure due to pore compaction.…”

Section: Factors Affecting the Electrical Properties Of Sandstonementioning

confidence: 89%

Simulation of Rock Electrical Properties in Deep Reservoirs Based on Digital Rock Technology

et al. 2023

View full text Add to dashboard Cite

Deep reservoirs are in a high-pressure and high-temperature (HPHT) environment, while the experimental conditions for rock electrical properties that meet the deep reservoir conditions are harsh and costly. Although digital rock technology can simulate the electrical properties of rocks, it is limited to electrical simulation studies under normal temperature and pressure conditions (NPT), which limits their ability to capture the electrical characteristics of deep hydrocarbon reservoirs. This limitation affects the accuracy of saturation prediction based on resistivity logging. To simulate the rock electrical properties under HPHT conditions, we proposed a low-cost and high-efficiency HPHT digital rock electrical simulation workflow. Firstly, samples from deep formations were CT-scanned and used to construct multi-component digital rocks that reflect the real microstructure of the samples. Then, mathematical morphology was used to simulate the overburden correction under high-pressure conditions, and the changes in the conductivity of formation water and clay minerals at different temperatures were used to simulate the conductivity changes of rock components under high-temperature conditions. To carry out the electrical simulation of digital rock in deep reservoirs, a numerical simulation condition for HPHT in deep layers was established, and the finite element method (FEM) was used. Finally, based on the equivalent changes in the conductivity of different components, the effects of clay minerals and formation water under HPHT conditions on rock electrical properties were studied and applied to predict the water saturation based on well logging data. We found that considering the influence of temperature, salinity, and clay type, the saturation index (n) of the rock depends on the ratio of the clay conductivity to the formation water conductivity. The larger the ratio is, the smaller the value of n. In addition, the average relative error between the predicted water saturation under HPHT conditions and the sealed coring analysis was 6.8%, which proved the accuracy of the proposed method. Overall, this method can effectively simulate the pressure and temperature environment of deep formations, reveal the electrical conductivity mechanisms of rocks under formation pressure and temperature conditions, and has promising prospects for the study of rock physical properties and reservoir evaluation in deep formations.

show abstract

Section: Factors Affecting the Electrical Properties Of Sandstonementioning

confidence: 89%

Simulation of Rock Electrical Properties in Deep Reservoirs Based on Digital Rock Technology

et al. 2023

View full text Add to dashboard Cite

show abstract

“…Later on, acknowledging the variable level of water saturation along hydrocarbon zone, dynamic electrical rock typing (DERT) was developed by Soleymanzadeh et al (2021a, b) for the prediction of saturation exponent ( n ) at un-cored depths. Kolah-kaj et al (2021) investigated the effect of pressure on ERTs. Besides, some efforts have been made to predict consequential porous media properties based on the concept of EQI (Soleymanzadeh, Kolah-kaj, et al 2021, 2022.…”

Section: Eqi Conceptmentioning

confidence: 99%

“…Kolah-kaj et al (2021) investigated the effect of pressure on ERTs. Besides, some efforts have been made to predict consequential porous media properties based on the concept of EQI (Soleymanzadeh, Kolah-kaj, et al 2021, 2022.…”

Section: Eqi Conceptmentioning

confidence: 99%

Electrical rock typing using Gaussian mixture model to determine cementation factor

Najafi-Silab

Soleymanzadeh

Kolah-kaj

et al. 2023

J Petrol Explor Prod Technol

Self Cite

View full text Add to dashboard Cite

Many studies have worked on the estimation of fluid saturation as an important petrophysical property in hydrocarbon reservoirs. Based on Archie's law, proper determination of cementation factor (m) can lead to accurate values of water saturation. Given that the m is mainly affected by electrical properties of rock, electrical quality index (EQI) can be used to estimate m through a novel rock typing technique. Despite the efficient applicability of EQI for the classification of rocks, with similar electrical behaviors, into distinct electrical rock types (ERTs), manual implementation of this method is time-consuming and gets excessively more difficult for larger datasets. In this work, a fast automated version of EQI methodology was presented. As a fuzzy clustering algorithm, Gaussian mixture model (GMM) was implemented on a large quantity of carbonate and sandstone samples to cluster them into distinct ERTs based on EQI values. To this end, 100 data points were randomly selected for testing purposes, and the remaining data points were used as training subsets for carbonate and sandstone samples. An innovative hybrid EQI-GMM approach was developed to determine the optimum number of clusters. Furthermore, results of two commonly-used criteria, namely Schwarz's Bayesian Criterion (BIC) and Akaike Information Criterion (AIC), showed that they fail to specify ERTs properly. The predicted values for m by the hybrid EQI-GMM approach were more accurate (RMSE is 0.0167 and 0.0056 for carbonate and sandstone samples, respectively) than outputs of the traditional Archie’s law (RMSE is 1.6697 and 0.1850 for carbonate and sandstone samples, respectively).

show abstract

“…Soil resistivity mainly depends on the porosity, pore water, solid particle composition, and cementation state, and the concepts of structural factor, resistivity index, and apparent resistivity structure factor of the rock and soil media have been proposed through resistivity logging by some scholars in the early stage [7][8][9][10] . In recent years, with the development of resistivity theory, the structural characteristic parameters of resistivity have been gradually applied to the study of the microstructure, hydromechanical, and structural properties of various soils [11][12][13] , especially the evaluation analysis of special physical and mechanical properties of regional soils 14,15 . The resistivity method has shown to be an effective tool for studying the structural properties of soil with the advantages of fast and nondestructive testing.…”

Section: Introductionmentioning

confidence: 99%

A resistivity-based experimental compaction model for Yunnan laterite

Peng

Zhao

et al. 2023

Preprint

View full text Add to dashboard Cite

Soil resistivity can effectively reflect the variation in structural characteristics of soils. The changes in soil resistivity can indirectly represent the degree of soil compaction, which is of great significance for the rapid evaluation of soil compaction. Yunnan laterite, in China, has widely been used as a building material in foundations, roadbeds, and dams due to its high strength and low compression. In this work, we tested the vertical and lateral resistivity of laterite during consolidation compression through an improved consolidation compression resistivity tester to discuss the variations in resistivity structural characteristic parameters (structural factor, shape factor, and anisotropy coefficient). A comprehensive index of resistivity structure characteristics was proposed to create a compactness evaluation model of laterite. The results showed that the vertical resistivity, lateral resistivity, average structural factor, and average shape factor of laterite gradually increased with continuous multi-stage vertical loading; however, the anisotropy coefficient decreased first, and then slowly increased to a stable state. The comprehensive index of resistivity structure characteristics could indirectly reflect the water content and pore content of the laterite, and the lateral resistivity was predicted from the vertical resistivity. Considering the influence of saturation and porosity on the resistivity structure characteristics, the evaluation model of compaction for laterite was finally established based on resistivity characteristics and this model had high accuracy, with small model verification error and good applicability. The proposed prediction model could serve as a theoretical reference for the application of the high-density electrical method in the convenient detection of compaction for laterite rolling engineering.

show abstract

The effect of pressure on electrical rock typing, formation resistivity factor, and cementation factor

Cited by 13 publications

References 32 publications

Simulation of Rock Electrical Properties in Deep Reservoirs Based on Digital Rock Technology

Simulation of Rock Electrical Properties in Deep Reservoirs Based on Digital Rock Technology

Electrical rock typing using Gaussian mixture model to determine cementation factor

A resistivity-based experimental compaction model for Yunnan laterite

Contact Info

Product

Resources

About